1. Field of the Invention
The present invention relates generally to a method of controlling an automatic guided vehicle system, and more particularly, to a method of controlling an automatic guided vehicle system having a plurality of automatic guided vehicles, which is capable of efficiently managing the automatic guided vehicles.
2. Description of the Related Art
In general, an Automatic Guided Vehicle system is used to automate loading and conveying of articles, and employs an Automatic Guided Vehicle (AGV). The AGV is an apparatus used to move loaded articles along a guideline located on the ground. A continuous guideline made of a magnetic tape is installed on a moving path of the AGV, and the AGV detects the guideline via a magnetic sensor, so that the AGV travels along the continuous guideline.
FIG. 1A is a schematic diagram illustrating an operation of a conventional AGV system. Referring to FIG. 1A, in the conventional AGV system, a single AGV 20 carries out tasks J1, J2 and J3 on a moving path 10 along which the tasks J1, J2 and J3 exist. In this case, the AGV 20 receives task commands transmitted from a main control unit 30, and then performs the tasks while traveling along the moving path 10. The AGV 20 performs the tasks according to an order in which the task commands are received.
FIG. 1B is a flowchart illustrating an operation of the conventional AGV system. Referring to FIG. 1B, the AGV 20 initializes data at operation S10. If the initialization of the data is completed, the AGV 20 receives task commands from the main control unit 30 and sets the order of the tasks to be performed according to the task commands at operation S20. In this case, the AGV 20 sets the order of the tasks to correspond to the order of reception of the task commands transmitted from the main control unit 30 in accordance with a First-In First-Out (FIFO) rule. According to the FIFO rule, a task command which is input first is the task command which will be output and performed first by the AGV 20.
Thereafter, it is determined whether preparation of the AGV 20 to perform the tasks has been completed at operation S30. If the preparation of the AGV 20 to perform the tasks has been completed, the AGV 20 performs the tasks while traveling along the moving path 10 according to the order of tasks set at operation S20, at operation S40. Thus, the AGV 20 first performs a task corresponding to a first received task command based on the FIFO rule as described above. Thereafter, it is determined whether a current task has been completed at operation S50. As a result, if the current task has been completed, it is determined whether all the tasks corresponding to the received task commands has been completed at operation S60. If all the tasks have been completed, a process of the operation of the conventional AGV system is terminated.
As described above, the conventional AGV system has the single AGV and first performs the first received task command according to the FIFO rule. That is, in the case where the conventional AGV system is operated in the order of tasks (i.e., task J1, task J2 and task J3), the AGV 20 first performs the task J1, passes the task J2, moves to a location of the task J3 and secondly performs the task J3. Thereafter, the AGV 20 performs the task J2 after moving to a location of the task J2.
Accordingly, since the conventional AGV system uses a single AGV and first performs a first received task without taking a moving distance of the AGV into consideration, the moving distance of the AGV becomes unnecessarily long and consumes too much time to carry out tasks, thereby deteriorating efficiency of completing the tasks and productivity.